Piano-action.



No. 736,920; BATE/NTBD AUG. 25,1903.

- a. A. AHLSTRQM. V

PIANO ACTION."

APPLICATION FILED NOV. 3. 1902. F0 X01321...

1: PL I WITNESSES INVENTOR .7 ATTORNEY 1 dotted outline in Fig.

- UNITED i "i J..-

Patented August 25', 1908.

-OFFICE.

CHARLES A. AHLSTRQliI, UF QJAMES'rOWmnEW YORIQ Puts o-Ao ioN;

SPECIFICATION forming part of. Letters Patent No. 736,92o, dated August 25, 1908i Application filed November 3, 1902. Serial No. 129.824. (Ho model.)

To all whm it may concern.-

Be it known that 1, CHARLES A. AHLSTROM, a citizen of the United States, and a resident of Jamestown, in the county of Chautauqua and State of New York, have invented a new and useful Piano-Action, of which the following, taken in connection with the accompanying drawings, is a full and clear description.

My invention relates to piano-actions; and the object of my invention is to provide a positive uniform means for controlling or regulating the position of the back-check as against climatic changes and-which prevents the back-checks and hammers from blocking solidly against the strings and stopping all sound and which also provides an eflective check for the hammers when brought into close proximity to the strings in producing softor fine aeolian sounds.

In the accompanying drawings, Figure 1 is a sectional view of a piano-action with my improved stop-rail and back-check, showing the key depressed, the hammers 'near the string, and the back-check held by the stop rail. Fig. 2is a perspective yicw of an ac-. tion-bracket and my stop-rail with-back-check and hammer-heel.

Similar numerals refer to corresponding parts in the several views.

The numeral isa key of an upright piano, which has the capstan-screw 11 in its rear end. The extension- 12 rests on capstan 11 and raises the front end of wippen 13, with jack 14 thereon and hammer 15 in the usual manner in striking string 16. The rear end of the wippen 13 is lowered by the raising of the front end and causes wire-spoon 17 to press out on damper-lever 1S, withdrawing damper 19 from the string 10, as usual. The hammerrail 20 is raised by the usual trap-work and pedal from its normal position, as shown in 1, to any desired position in holding the hammers in proximity to the strings.

I make my back-checks 22 with an extension 26 attheir upper ends, as compared with the old form which is shown in dotted outline at 27. A stop-rail 21 is secured on action-snpportingbrackets 23 by suitable screws 24 in such a position in the path of back checks 22 as to prevent the back-check from, springing forward againstthejia nmer-butt heel 15 and blocking the hammer 15against the string. The openings in rail 21 for screws 242 are made somewhat larger than the'screw in order that rail 21 may be adjusted or regulated as desired. The opposing faces ofhal nmer-butt heel 15 and back-cheek 22 arefelted in the usual manner, and the edge 25 of rail 21 is burnished or black leaded to insure smooth noiseless action.

It is obvious that when, as shown in Fig. 1, key 10 is depressed by the player,and thereby extension 12 raises wippen 13 and back-check 22, the back-check can only advance in its upward-and-forward motion until it strikes stop-rail 21.

ing such upward and forward position of the back-cheeks, no matter how much the parts Stop-rail 21 therefore becomes aposi tive or -fixed limit for such upward motion and is thus a positive means of regulatmay be out of regulation by dampness or other causes. The position of stop-rail 21 is that which has been experimentally found to be the exact position for the back-checks in or- -75. der to best receive the rebound of the hammer-butt heel and produce the best tonal ef feets. Rail 21 is capable of regulation or adjustment, as stated; but when once secured in this predetermined position it is positive and uniform in its reception of the faces of the back-checks and forms the upper limit of their journey. It is also apparent that pressin g the back-checks against the straightedge of my stop-rail keeps the back-checks in true line and in correct position, and that thus the stop-rail controls or regulates the position of the back-checks, as stated.

All who are skilled in the art of piano making and regulating realize the care and skill which must be exercised in adjusting backcheeks22 in order that they shall rightfully perform their ofiice; but after the highest skill has been exercised it is found that dampness will cause the wood parts of the action to swell, forcing checks 22 forward shflieiently to cause theblocking of the hammers solid against'the strings instead of having room to spring back agains t ,thie-back-check, as they 1 appar fit, at once that 'my simple stop rail'21'and extension 26 ofback-chec s22 en Fig. 1, and the keys are touched lightly the most beautiful soft tonal effects may be pro- 10 duced, as of an aeolian harp. Without my stop-rail the back-checks spring forward and block such light touches on the strings; but with it the hammers are free to be actuated by the lightest touches on the keys, thus'pr'of :5 ducing new and most pleasing efiects,

What'I claim as new, and desire to secure by Letters-Patent, isy 1. In a piano-action, suitable wippens and means for actuating the same, back-checks on 20 said wippens and moved thereby, and a positive regulating means to limit said movement of the back-checks.

2. In a piano-action, suitablewippens and means for actuating the same, back-cheeks on said wippens and actuated thereby, a stop-rail to limit said movementof the back-checks.

mers and means for actuating the same, backehecks having felt-faced extensions, and a positive stop-rail to receive said felt-faoed extensions. I

- 4. A piano-action having suitable supportr mers actuated by saidjacks', back-checks on -ets,-and a straight side to said rail to receive L said back-checks and equalize their movement.

- In testimony-whereof I have signed my name to this specification in the [presence of two subscribing witnesses;

, CHARLES A. AHLSTROM;

- Witnesses:

A. W. KETTLE,

S. ARTHUR BALDWIN.

3. In a,piano-action having suitable ham ing-brackets, wippens having jacks thereon and means for actuating said wippens, ham q t '35 said wippens and actuated thereby, a regulating=rail for the back-checks on said brack- 

